A bonding wire electrically connects between a semiconductor chip and an outer electrode in a conventional semiconductor device as a surface-mount device disclosed in Japanese Patent Publication (Kokai) No. 2006-278520. The semiconductor device using wire-bonding is simply shown in FIG. 16, for example, and is explained below.
A semiconductor device 1000 includes a semiconductor chip 1001 having a surface electrode 101a and a back surface electrode 1001b on the front surface and the back surface, respectively. An outer electrode 1002 is connected to the back surface electrode 1001b of the semiconductor chip 1001 via a conductive material (not shown) and the surface electrode 1001a of the semiconductor chip 1001 is connected to an outer electrode 1003 by a bonding wire 1004. The semiconductor device 1000 is encapsulated to be airproofed by an encapsulation resin 1005. In the semiconductor device 1000, wiring pads 1007 configured on a substrate 1006 are mutually connected via the outer electrodes 1002 and 1003 and a conductive material (not shown).
Further, as a feature of other small-type electronic device, for example, a type as shown in FIG. 17 can be listed. A semiconductor device 1010 is constituted with a stacked capacitor 1011 and a pair of outer electrodes 1012 connected to the both ends of the stacked capacitor 1011, respectively. A semiconductor chip (not shown) is disposed in the stacked capacitor 1011. Five surfaces of the outer electrode 1012 other than the surface connected to the stacked capacitor 1011 act as an electrode. Furthermore, the outer electrode 1012 is disposed on wiring pads 1014 configured on a substrate 1013. As shown in FIG. 17, a solder 1015 is disposed on the wiring pads 1014 and the outer electrode 1012. The substrate 1013 and the semiconductor device 1010 are electrically connected by the solder 1015.
However, the semiconductor device using the bonding wire disclosed in Japanese Patent Publication (Kokai) No. 2006-278520 has problems mentioned below.
Improvement of electrical characteristics of electron devices, for example, has been desired according to popularization of a cell phone or electronics. An electrical resistance of a bonding wire is increased in the semiconductor device by using the bonding wire. Therefore, improvement in electric characteristics is difficult. Furthermore, as shown in FIG. 16, the surface electrode 1001a of the semiconductor chip 1001 is individually connected to the outer electrode 1003. Consequently, decrease of steps in a fabrication process and shortage of takt time cannot be performed so that productivity cannot be improved.
As shown in FIG. 17, the semiconductor device has the structure that the semiconductor chip is encapsulated in the stacked capacitor. The structure can be improved in electric characteristics due to non-bonding wire as compared to the semiconductor device 1000 having the bonding wire.
On the other hand, a problem may occur when the semiconductor chip is encapsulated. The problem is that the semiconductor element in the semiconductor device is failed. The stacked capacitor 1011 is laminated with hard insulators sandwiching as shown in FIG. 17 and is fabricated by thermocompression. When encapsulating the semiconductor chip, a load to the semiconductor chip may provide damages to the semiconductor chip, which leads to degradation of yield in the fabrication process. Furthermore, peeling between the semiconductor chip and the material sandwiching the semiconductor chip at a contacting interface may be generated in reliability test or a shock accompanying with falling, which may lead to degradation of yield in the fabrication process.
Further, next process may be used as an example for a method for fabricating the semiconductor device 1010 as shown in FIG. 17. First, a semiconductor chip configured to be rearranged by forming a street portion with a prescribed interval is resin-encapsulated. Subsequently, holes for connecting between an electrode and an outer electrode 1012 formed on a front surface and a back surface of the semiconductor chip, respectively, are formed in the resin by a laser process. An outer electrode 1012 is formed by plating. Energy, mainly thermal energy, applied by the laser in the laser process to the semiconductor chip can remove a protect film constituted with, for example, Ni, Au or the like as a metal formed on an electrodes on the front surface and the back surface of the semiconductor chip. The state is not good as the electrode. Thickening the protect film can be considered, however, excess material may be necessary. Further, it is necessary to individually form the holes in the all electrodes of the semiconductor chips. Much more time is necessary for the laser process.
When one surface of the semiconductor chip is resin-encapsulated, the encapsulating resin is heated to be hardened and the temperature is lowered down to room temperature in the resin encapsulation. Accordingly, warpage can generate in a work constituted with the wafer and the encapsulating resin.
This invention is carried out to be solved the problem mentioned above. This invention provides the semiconductor device and the method for fabricating the semiconductor device having a structure without using a bonding wire so as to improve electrical characteristics, to retain high reliability, to promote shortage of takt time in the processing steps and to improve productivity by deleting the laser process.